diff --git a/config.yml b/config.yml
index b5865d6..119fdf0 100644
--- a/config.yml
+++ b/config.yml
@@ -22,3 +22,7 @@ region: eu-west-1
 
 # Client ID of the oAuth2 application created in the Google Cloud console
 google_client_id: 693734536874-s0quna7oa2msnt1up4vubi4sh3uaucud.apps.googleusercontent.com
+
+# Theme name (lowercase) of Bootswatch.com theme (Optional, when not
+# specified the original bootstrap theme is used)
+bootswatch_theme: cosmo
diff --git a/index.html b/index.html
index 7721ab3..a98f713 100644
--- a/index.html
+++ b/index.html
@@ -17,6 +17,10 @@
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css"
           integrity="sha256-eZrrJcwDc/3uDhsdt61sL2oOBY362qM3lon1gyExkL0=" crossorigin="anonymous" />
 
+    {% if bootswatch_theme %}
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootswatch/3.3.7/{{ bootswatch_theme }}/bootstrap.min.css" />
+    {% endif %}
+
     <style>
       #signInButton { margin: 20px 164px 0; }
       .modal-body { text-align: center; }